A systematic review of carbon accounting in macroalgae.

With the growing interest in macroalgae (seaweed) as a carbon sink and its potential for carbon trading, the accounting community has increasingly focused on this area. However, confusion persists regarding existing measurement and assessment methods, and there is a lack of systematic studies on macroalgal carbon sink accounting. This study reviews 132 research articles on macroalgal carbon accounting, focusing on measurement (field studies, laboratory experiments, and remote sensing technologies) and assessment (stock-difference approach, bio-ecological modeling, and life cycle assessment - LCA) methods. The analysis shows that 42.4 % of the literature focuses on measurement methods, with laboratory experiments accounting for 31.8 %. Assessment methods represent 28 % of the literature, with LCA accounting for 10.6 %. Additionally, 22.7 % of the literature examines both types. The study reveals a complementary relationship among the existing methods, highlighting the critical role of measurement data. While the stock-difference approach is widely used, the study identifies the need to enhance the application of remote sensing technologies and expand research on LCA to improve the accuracy of carbon accounting. Furthermore, carbon management of large-scale cultivation of macroalgae plays a significant role in achieving the Sustainable Development Goals (SDGs). The integrated multi-trophic aquaculture and advancements in emission reduction technologies offer effective strategies for enhancing carbon sequestration and promoting sustainable carbon management.